Pulse regenerator comprising a transistor regeneratively fed back by a saturable core and a linear core



Dec. 1, 1964 J. DOMBURG E PULSE REGENERATOR COMPRISING A TRAIIS I TOR REGENERA TI VELY 12 1 I L T: 13 .A.

PRIOR ART 5 CORE 1: EEGENERATIVE \L- DRWEN LOAD FEEDBACK VIA SATURABLE CORE, EFFECTIVE FOR 5 DURATION OF BLOCKING PULSE. 3 2O 11 CORE 1s= REGENERATIVE FEEDBACK VIA LINEAR RESET 12 1 8 1 CORE, EFFECTIVE AT PULSE SOURCE 4 TURN ON AND OFF.

13 A 14 21 TRIGGER PULSE SOURCE 2 INVENTOR JAcoBus DOMBURG. MCOB MULDER.

United States Patent This invention relates to a pulse regenerator. In particular, it relates to such a regenerator having two stable states which, after reception of a pulse while in one of the stable states, can automatically pass into the other stable state while producing a pulse; the regenerator broadly comprises a self-blocking oscillator in which a transistor is fed back in the positive sense through windings on a core consisting of a magnetic material having a rectangular hysteresis loop.

The object of the invention is to provide a regenerator of the above type in which the regenerated pulses have an improved shape.

in order that the invention may readily be carried into effect, one embodiment thereof will now be described, by way of example, with reference to the accompanying drawing, in which,

FIG. 1 is a known pulse regenerator.

FIG. 2 is an embodiment of a pulse regenerator according to the invention.

FIG. 3 shows two curves giving the relationship between the magnetic flux density B and the magnetic field strength H, to illustrate the action of the regenerators shown in FIGURES l and 2. In the figures, corresponding elements are referred to by the same reference numerals.

In FIG. 1, reference numeral 1 is a core consisting of magnetic material having a rectangular hysteresis loop which is represented by curve 2 in FIG. 3. A winding 3 on the core 1 is included in the collector circuit of the transistor 4 (shown as a pup type) in series with a load 5, a current-determining resistor 6 and a supply battery 7. A winding 8 is connected between ground and the base electrode of transistor 4. The windings 3 and 8 provide a positive feedback coupling from the collector circuit to the base-circuit. Due to the positive feedback connection, an increase of the collector current results in a decrease of the voltage at the base electrode.

in the rest condition, i.e., in the condition in which no currents are flowing, core 1 is in either of the two remanence conditions which are indicated in FIG. 3 by the points 9 and 10. The core may be brought into the condition 10 by a pulse from the pulse source 11 which is coupled to the winding 12. The pulse source 11 may in turn be a pulse regenerator of the type described above. The tranisition from the remanence condition 10 to the condition 9 is achieved by a pulse from pulse generator 13 which can supply pulses to the winding 14. Such a pulse causes a negative induction change in the core, as a result of which the induction decreases from point 10 along branch 15 of curve 2 in FIG. 3.

The dots which are shown on the one side of the windings of the core 1 indicate that the side of a winding so marked has a positive voltage induced therein with respect to the other side in the case of a positive induction change in the core. It can be seen that a pulse of generator 13 causes a negative voltage to appear at the base electrode of transistor 4. As a result, the transistor becomes conductive.

It is known to design the regenerator in such a way that the transistor starts conducting regeneratively and is controlled into the saturation condition.

3,159,752 Patented Dec. 1, 1964 ice After the beginning of the regenerative action, the pulse from generator 13 may be discontinued.

The collector current magnetizes the core in the nega tive sense, as a result of which the magnetic flux density further decreases along branch 15. The base current slowly decreases after the initial strong increase.

It is also known in the prior art to design the regenerator so that the magnetic flux density of the core reaches the saturation branch 16 of curve 2 before the transistor leaves the saturation condition achieved due to the decreasing base current. As a result of this, the magnetic flux density, after termination of the collector current pulse, reaches the remanence point 9 and is prevented from passing into a higher-situated remanence condition such as indicated for example by point 17. At the instant at which the magnetic flux density reaches branch 16, the negative voltage induced in the winding 8 suddenly decreases. Therefore, the base current further decreases and the transistor will leave the saturation condition.

The transistor effect is based on diffusion of charge carriers injected into the base by the emitter, from the base-emitter transition to the base-collector transition. When the transistor is in the conductive condition, the charge concentration in the base is many times larger than in the non-conductive condition; therefore, charge has to be supplied during the turn-on phase, and charge has to be conducted away in the turn-off phase. Further, the base current is equal to the sum of the number of injected charge carriers which, per unit time, recombine with majority carriers, and the change of the charge per unit time.

Assume that the base current in the regenerator described'has decreased to substantially the value zero. The charge concentration in the base then decreases by recombination only. This is a comparatively slow process. Therefore, also the collector current slowly decreases. In the collector circuit a current pulse is formed having a small rise time and a comparatively large decay time. During the trailing edge of the collector current pulse, the magnetic flux density of the core passes along branch 16 to the remanence point '9. In this case, the strength of the magnetic flux density does not substantially change and no voltage is induced in winding 8.

Referring now to FIG. 2, reference numeral 18 is a core consisting of magnetic material having a low remanence (linear core). Curve 19 in FIG. 3 shows the relationship between the magnetic flux density B and the field strength H, the core 18 being assumed to have zero remanence. Core 18 has a winding 20 in the collector circuit of transistor 4 and a winding 21 in its base circuit. These windings provide a feedback coupling in the posi tive sense from the collector circuit to the base circuit.

In the same manner as in FIG. 1, a pulse from the pulse source 11 can bring the core 1 into the condition It) and a pulse from the pulse generator 13 can start the transition from the condition 10 into the condition 9. The regeneratively achieved conductive action of transistor 4 takes place in the same manner as in FIG. 1, but the additional feedback coupling via core 18 may accelerate the process. The magnetic flux density of core 1 decreases along branch 15 of curve 2. The magnetic flux density in core 18 decreases along curve 19. After the magnetic flux density in core 1 has reached the saturation branch 16, the voltage induced in the winding 8 decreases to the value 0. As a result, the base current decreases and the transistor will leave the saturation condition. The magnetic flux density in core 1 passes along branch 16 to the remanence point 9 and the magnetic flux density of core 18 passes along curve 19 to the origin where the remanence is 0, as soon as the collector current decreases. density in core 18 induces a positive voltage in winding The positive change of the magnetic flux 21, as the result of which the base voltage increases. The direction of the base current now reverses. This means that the base electrode conducts away majority charge carriers from the base as a result of which the concentration of the charge carriers injected into the base may decrease rapidly. Therefore, the collector current also decreases rapidly. This in turn results in the magnetic flux density in core 18 increasing more rapidly, as a result of which the transistor may regeneratively pass into the non conductive condition in an avalanche-like manner. The collector current pulse therefore has both a small rise time and a small decay time.

While the invention has been described With respect to a specific embodiment, many modifications and variations thereof are possible. It is therefore to be understood that, within the scope of the appended claims, the invention may be practiced otherwise than as specifically described.

What is claimed is:

l. A pulse regenerator comprising: a first magnetic core consisting of a magnetic material having a substantially rectangular hysteresis curve, a trigger winding inductively coupled to said first core, means for applying a trigger pulse to said trigger winding, an output winding inductively coupled to said first core, a load connected to said output winding, a third winding inductively coupled to said first core, a second core consisting of magnetic material having a substantially linear hysteresis curve, a transistor having an output electrode, an input electrode, and a common electrode, first and second windings inductively coupled to said second core, said output winding and the first winding of the second core being connected in series with the output electrode of the transistor, the load, and the common electrode, said third winding and the second winding of the second core being connected in series with the input electrode and the common electrode of the transistor, said output winding and said third Winding of the first core and said first and second windings of of the second core providing regenerative feedback between said output and input electrodes upon the application of a trigger pulse and producing an output pulse across said load having a short rise time and a short decay time.

2. A pulse regenerator as recited in claim 1 wherein s said output electrode is the collector electrode, said input electrode is the base electrode, and said common electrode is the emitter electrode.

3. A pulse regenerator as recited in claim 1 further comprising a reset winding inductively coupled to said first core and means for applying a reset pulse to said reset Winding.

4. A pulse regenerator comprising: a first saturable magnetic core consisting of a magnetic material having a substantially rectangular hysteresis curve, a trigger winding inductively coupled to said first core, means for applying a trigger pulse to said trigger winding, an output winding inductively coupled to said first core, a load connected to said output Winding, a third winding inductively coupled to said first core, a second non-saturable magnetic core consisting of a magnetic material having a substantially linear hysteresis curve, a plurality of windings inductively coupled to said second core, a transistor having an output electrode, an input electrode and a common electrode, said output winding and one or more of the windings of said second core being connected in series with the output electrode of the transistor, the load, and the common electrode, said third winding and one or more windings of said second core being connected in series with the input electrode and the common electrode of the transistor, the connections between the output and input electrodes and the associated windings providing regenerative feedback between said output and input electrodes upon the application of a trigger pulse and producing an output pulse across said load, the saturable characteristic of said first core acting to reduce the voltage at said input electrode after the core reaches saturation in one direction, the linear characteristic of said second core acting to increase the voltage at said input electrode after the first core reaches saturation in said one direction, thereby producing an output pulse having a short rise time and a short decay time.

Polzin et a1 Feb. 23, 1960 Lund Sept. 13, 1960 

1. A PULSE REGENERATOR COMPRISING: A FIRST MAGNETIC CORE CONSISTING OF A MAGNETIC MATERIAL HAVING A SUBSTANTIALLY RECTANGULAR HYSTERESIS CURVE, A TRIGGER WINDING INDUCTIVELY COUPLED TO SAID FIRST CORE, MEANS FOR APPLYING A TRIGGER PULSE TO SAID TRIGGER WINDING, AN OUTPUT WINDING INDUCTIVELY COUPLED TO SAID FIRST CORE, A LOAD CONNECTED TO SAID OUTPUT WINDING, A THIRD WINDING INDUCTIVELY COUPLED TO SAID FIRST CORE, A SECOND CORE CONSISTING OF MAGNETIC MATERIAL HAVING A SUBSTANTIALLY LINEAR HYSTERESIS CURVE, A TRANSISTOR HAVING AN OUTPUT ELECTRODE, AN INPUT ELECTRODE, AND A COMMON ELECTRODE, FIRST AND SECOND WINDINGS INDUCTIVELY COUPLED TO SAID SECOND CORE, SAID OUTPUT WINDING AND THE FIRST WINDING OF THE SECOND CORE BEING CONNECTED IN SERIES WITH THE OUTPUT ELECTRODE OF THE TRANSISTOR, THE LOAD, AND THE COMMON ELECTRODE, SAID THIRD WINDING AND THE SECOND WINDING OF THE SECOND CORE BEING CONNECTED IN SERIES WITH THE INPUT ELECTRODE AND THE COMMON ELECTRODE OF THE TRANSISTOR, SAID OUTPUT WINDING AND SAID THIRD WINDING OF THE FIRST CORE AND SAID FIRST AND SECOND WINDINGS OF OF THE SECOND CORE PROVIDING REGENERATIVE FEEDBACK BETWEEN SAID OUTPUT AND INPUT ELECTRODES UPON THE APPLICATION OF A TRIGGER PULSE AND PRODUCING AN OUTPUT PULSE ACROSS SAID LOAD HAVING A SHORT RISE TIME AND A SHORT DECAY TIME 